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Test I: Blower Motor Inoperative - Auxiliary

WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
NOTE: Definition: The auxiliary blower motor is inoperative in all speed positions.
  1. If review of system operation has been performed, go to next step. If review of system operation has not been performed, see DESCRIPTION  and OPERATION  .
  2. Turn ignition on. Place front auxiliary blower switch in each speed position. If auxiliary blower motor is inoperative in all speed positions, go to step  4. If blower motor does operate in all speed positions, go to next step.
  3. Turn headlights on. Place instrument panel light dimmer switch in the brightest position. Place front auxiliary blower switch in each speed position. If auxiliary blower motor is inoperative in all speed positions, go to step  9. If blower motor does operate in all speed positions, go to TEST J: BLOWER MOTOR MALFUNCTION - AUXILIARY .
  4. Turn ignition off. Disconnect harness connector from auxiliary blower motor. Turn ignition on. Using a test light connected to ground, probe voltage supply circuit (Yellow wire) at blower motor harness connector. Place front auxiliary blower switch in maximum speed position. If test light illuminates, go to next step. If test light does illuminate, go to step  6.
  5. Connect a test light between auxiliary blower motor voltage supply circuit (Yellow wire) and auxiliary blower motor ground circuit (Black wire) at auxiliary blower motor harness connector. Place front auxiliary blower switch in maximum speed position. If test light illuminates, go to step  11. If test light does illuminate, go to step  13.
  6. Check auxiliary blower motor voltage supply circuit (Yellow wire) for an open, high resistance or a short to ground. If an open, high resistance or a short to ground was found, repair as necessary and go to step  16. If an open, high resistance or a short to ground was not found, go to next step.
  7. Check ignition 3 voltage circuit (Brown wire) to blower motor relays for an open, high resistance or a short to ground. See WIRING DIAGRAMS . If an open, high resistance or a short to ground was found, repair as necessary and go to step  16. If an open, high resistance or a short to ground was not found, go to next step.
  8. Check positive battery voltage circuit (Red wire) to blower motor relays for an open, high resistance or a short to ground. See WIRING DIAGRAMS . If an open, high resistance or a short to ground was found, repair as necessary and go to step  16. If an open, high resistance or a short to ground was not found, go to next step.
  9. Check applicable blower motor speed control circuit for a short to ground. See WIRING DIAGRAMS . If a short to ground was found, repair as necessary and go to step  16. If a short to ground was not found, go to next step.
  10. Check ground circuit (Black wire) of auxiliary blower switch (auxiliary heat only), or front auxiliary HVAC control assembly (auxiliary HVAC) for an open or high resistance. See WIRING DIAGRAMS . If an open or high resistance was found, repair as necessary and go to step  16. If an open or high resistance was not found, go to step  12.
  11. Check harness connector at auxiliary blower motor for a poor connection. If a poor connection was found, repair as necessary and go to step  16. If a poor connection was not found, go to step  14.
  12. Check harness connector at auxiliary blower switch (auxiliary heat only), or front auxiliary HVAC control assembly (auxiliary HVAC) for a poor connection. If a poor connection was found, repair as necessary and go to step  16. If a poor connection was not found, go to step  15.
  13. Repair the open condition in auxiliary blower motor ground circuit (Black wire). See WIRING DIAGRAMS . If the repair is complete, go to step  16.
  14. Replace auxiliary blower motor. See BLOWER MOTORS  under REMOVAL & INSTALLATION. After repairs are complete, go to step  16.
  15. Replace auxiliary blower switch (auxiliary heat only), or front auxiliary HVAC control assembly (auxiliary HVAC). See FRONT AUXILIARY HVAC CONTROL ASSEMBLY  or REAR AUXILIARY HVAC CONTROL ASSEMBLY  under REMOVAL & INSTALLATION. If replacement is complete, go to next step.
  16. Operate system to verify repair. If the condition was corrected, system is okay. If the condition was not corrected, return to step  2.
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